Valve structure



March 1968 1. A. FARNWORTH 3,371,967

VALVE STRUCTURE Filed Dec. 27, 1966 @EL 29 X 5 Sheets-Sheet 1 FIG. 3

L I INVENTOR'.

' i IVAN A. FARNWORTH BY W- FIG. IA W HIS ATTORNEY March 1968 A. FARNWORTH 3,

VALVE STRUCTURE Filed Dec. 27, 1966 5 Sheets-Sheet 2 INVENTOR IVAN A FARNWORTH HIS ATTORNEY Filed Dec. 27, 1966 March 5, 1968 FARNWORTH VALVE STRUCTURE 5 Sheets-Sheet 5 RC W 2 RT 2 ABC g c r so me A- 5 I p R L PAT FIG. 7 T R Il' ll ll" FIG. 8

INVENTOR- IVAN A. FARNWORTIH HIS TORNEY United States Patent 3,371,967 VALVE STRUCTURE Ivan A. Farnworth, 441 S. State, Orem, Utah 84057 Filed Dec. 27, 1966, Ser. No. 606,515 11 Claims. (Cl. 303-69) The present invention relates to valve structures and, more particularly, to a new and improved quick-release type valve mechanism for railway cars.

Accordingly, an object of the present invention is to provide a new and improved valve structure.

A further object of the invention is to provide a quickrelease type valve structure for railway cars which can be conveniently actuated so as to maintain reservoir pressure while bleeding the cars braking cylinder so that the car may be independently switched or otherwise transported without being boarded or hooked up to a train proper.

A further object of the invention is to provide a manually actuatable, self-resettable type quick release type mechanism for railroad cars, Which valve mechanism will be suitable for preventing actuation thereof in the ab sence of a minimum pre-determined reservoir pressure on the car.

A further object is to provide a new and improved braking system for railroad cars and, especially, an improvement therein, wherein the same is provided a novel quick-release valve mechanism for maintaining reservoir pressure for switching of individual cars.

A further object is to provide a new type of shuttle valve mechanism which is self-resetting.

A further object of the invention is to provide a quickrelease valve insert for insertion into the pneumatic braking system of a railroad car, which valve insert in neutral condition does not aifect normal braking operation but which, when actuated, will block and preserve reservoir pressure while the braking cylinder of the car is being exhausted.

A further object is to provide a quick-release valve mechanism for railway car braking systems wherein means are provided for simultaneously bleeding off the retainer line of the car with the braking cylinder thereof.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects, may best be understood by reference to the following description, taken in connection with the accompanying drawings in which:

FIGURE 1 is a longitudinal vertical section, taken along the line 11 in FIGURE 1A, of a quick-release value as contemplated by the present invention.

FIGURE 2 is a longitudinal, horizontal section, taken along the line 22 in FIGURE 1, of the valve of FIG- URE 1 wherein the section is taken along a plane defined by the axes of auxiliary valve bores in the body of the valve; for convenience of illustration, a certain portion is broken away and sectioned to illustrate the invention.

FIGURE 3 is a view similar to FIGURE 1 but illustrates the valve shuttle of the quick release valve as being translated to the left under admitted pressure to 3,371,967 Patented Mar. 5, 1968 FIGURE 7 is a fragmentary, schematic view showing the principal portion of the braking system of a railroad car which uses the present system as a braking system insert.

FIGURE 8 is a fragmentary, schematic view of a portion of the structure shown in FIGURE 7 wherein the valve has been actuated, this illustrating through flow of the pressured fluid utilized in valve operation.

Release valve means 10 is shown to include a valve body 11 provided with enlarged bore 12. A plug 13 is slideably journaled in the enlarged bore 12 and abuts compression spring 14, the latter likewise engaging shoulder 15 associated with enlarged bore 12. A rockable, actuating means 16 abuts the remaining side of plug 13 and is retained in position by a cap 17 threaded onto the valve body 11 as indicated. A Central aperture 18 is disposed in cap 17 and is suitably dimensioned so that a rocking action of rockable, actuating means 16, together with its integral actuating arm 19, may be accommodated. correspondingly, the outside diameter of the rockable, actuating means 16, preserably comprising a disc, will be somewhat reduced in size so as to accommodate for the rockable or tilting action of means 16. Arm 19 is pinned by pin 20 to clevis 21, and the latter is correspondingly pinned by pin means 22 to the conventional release rod 23 of a railroad car. Release rod 23 has conventionally formed release rod handles 24 and 25 integral therewith. Accordingly, movement, either back and forth or inward movement of the release rod 23 relative to the valve will cause a rocking or tilting of the disc or means 16 so as to produce an inward movement of valve stem 26, of valve gate 27 'of the valve X.

Now, valve body 11 includes stern bore 28 contiguous with enlarged bore 12, intermediate chamber 29 contiguous with the former, and chamber 30 contiguous with intermediate chamber 29, the juncture therebetween being formed by valve seat 31. Valve head 32 of valve gate 27 seats in valve seat 31. Valve spring 34 is a compression spring disposed between valve head 32 and threaded insert plug 35. It will be noted that the intermediate chamber 29 cooperates with passage 36, see also FIG- URE 2.

For design purposes it is believed advantageous to employ the valve gate 27 somewhat otf-centerwith respect to plug 13. Where such is the case, then extension 26, in a transverse direction of the valve stem 26, may well be provided to secure an overall abutment against plug 13 which is equalized relative to its center of mass. However, such extension need not in fact be supplied where spring pressures are not too great.

An auxiliary port 39 provides communication between chamber 34 and the principal chamber 40 of the valve. Valve chamber 40 includes a compression spring 41 which abuts seat 42, if provided, and medial partition 43 of valve shuttle 44. In a preferred embodiment of the invention the valve shuttle 44 is of generally cylindrical configuration and which includes bores 45 and 46, each terminating at a respective reaction face 47 and 48 of the aforementioned medial partition. Valve shuttle includes valve lands 49 and 50' and a medial portion disposed intermediate the valve lands and designated as 51. Suitable O-rings 52" and 53" are seated in respective grooves 54 and 55' of the two valve lands. Extension portion 56 of the valve shuttle is medially relieved at R to provide open chamber area 40, and is provided with radial perforations '57 which ofier communication between such extension portion and chamber 40 as delineated by recessed portion R of the extension portion. Flange 51 which is welded or otherwise secured to the valve body 11 is provided with function port 52 and source port 53, these being coaxially aligned with cor- 3 responding ports 52' and 53, respectively, of the valve body. A retainer line port 55 may also be provided but preferably does not find direct communication through the valve body 11 at that particular point. See FIG- URE 1.

Valve 6% includes a valve gate 61 provided with stem bore 62, medial chamber 63 contiguous therewith, and valve head chamber 64. Compression spring 64' is provided therein and abuts plug 69 and valve gate 61. Side bores 65' and 66 provide communication between chambers 63 and 64 and bores 67 and 68-, respectively, associated with retainer line port 55 and function port 52. The valve 6%) may be cast or welded to the valve body 11 in any conventional manner. It will be noted in FIG- URES and 6 that the valve 60 provides communication between ports 55 and 52 where the pressure at 55 exceeds that at 52. Where the pressures are equivalent or reversed, then conduction does not take place through valve 60.

Valve 70 includes valve gate 71 and valve seat 72. Valve gate 71 includes a conventional valve head 73, valve stem 74 integral therewith, and the valve seat 72 comprises the juncture formed between chamber 75 and the valve head chamber 76. Chamber 75 is contiguous with the stem journal bore 77. A compression spring 73 abuts valve head 73 and also plug 79. Auxiliary outlet port 80 is supplied and provides communication, see FIG- URE 2, between chamber 76 and the principal chamber 40.

In the drawings for convenience of illustration the stem bores are shown slightly enlarged.

Apertures 87 and 88 are simply mounting apertures which are conveniently provided for mounting the quickrelease valve to other structure.

The structure as thus far described operates as follows:

Release rod 23 will generally be mounted underneath the associated railroad car and immediately accessible for use. Movement of release rod 23 in direction of either of its handles 24 or 25, or general transverse movement of the release rod inwardly will cause a rocking of the rockable actuating means 16. This, in turn, produces a translation to the right of plug 13 and, correspondingly, of valve stem 26, thereby opening valve head 32 with respects to its seat 31. This opens this overall valve 27.

At this juncture it will be explained that function port 52 will be connected to the railway car brake cylinder, port 53 connected to the source of supply, i.e., the conventional AB valve generally supplied and connected to the associated reservoir and compressor, whereas port or chamber 55 will be connected to the retainer line, hereinafter explained. If port 53 is considered the source port, with the port 52 the function port, then pressured fluid media such as air or hydraulic fluid will flow into chamber 40 via source port 53 and thence out again, via function port 52, to the braking cylinder, not shown in FIGURES 16 (but see FIG- URE 7). This is by virtue of the fact that the medial portion 51 of the valve shuttle is relieved with respect to valve lands 50 and 49, thereby providing a portion of chamber 40 (i.e., 4%)") to be available for communication of fluid from source port 53 to and through function port 52. It will be seen hereinafter that appropriate regulation of the control or A-B valve produces the application of pressure to the braking cylinder, whereas positioning of the A-B valve in another direction operates to relieve air or other fluid from the braking cylinder back through, ports 52 and 53 to the A-B valve and from thence either exhaust the same directly or through a suitable retainer (e.g., a pressure relief valve).

Thus, with the valve shuttle 44 disposed in neutral condition as shown in FIGURE 1, the railroad car system will operate in a conventional manner. The neutral position of the valve shuttle. is determined through the use of return means 41 such as a return spring, and a stop means preferably taking the form of an end plug 95 against i which extension portion 56 of the valve shuttle abuts, see FIGURE 1.

When, however, a brakeman actuates release rod 23 as before described, see FIGURE 1, then valve 27 opens. But brief reference to FIGURE 2 indicates that this produces a communication from chamber 40- and through auxiliary outlet port 39, through and past the valve gate 27, past seat 31, through passageway 36 and, assuming the pressure is sufficiently large, opens valve gate 71 to permit the pressure fluid media to flow into chamber 76 and from thence downwardly through port to enter again chamber 40, but this time through chamber area 40' and perforations 57, to bear directly against reaction face 48. This, in turn, shifts the valve shuttle 44 from its position shown in FIGURE 1 (the neutral position) to an actuated position as shown in FIGURE 3. This action shifts O-ring 53" on valve shuttle 44 to the position indicated in FIGURE 3 wherein source port 53 and function port 52 are sealed oif. Hence, pressure is now retained by the quick release valve and blocked from communication therethrough. correspondingly, O-ring 5 shifts to the left to provide communication between function port 52 and exhaust port 97, see FIGURES 1 and 3. Hence, the air in the braking cylinder, for example, is now released through function port 52 to exhaust through the exhaust port 97.

For safety precautions it is deemed desirable to include the valve gate 71 and spring 78 so that if the pressure at the reservoir is at or below a predetermined minimum, or within a range below the predetermined minimum standard for operating of the valve, the second valve, i.e., valve Y, will not open, thus precluding movement of the valve shuttle to the left as seen in FIGURE 3 and corresponding release of brake pressure from the braking cylinder. This is especially desirable where the railroad car has proceeded down grade for a time and a substantial part of the pressure in the reservoir has been lost due to braking, and where subsequently the car is stopped.

It will be noted that the position of valve shuttle 44 will continue in its position as shown in FIGURE 3 until there is a sufficient reduction in pressure, once the A-B valve has been actuated to release the pressure at source port 53, to permit the return means or spring 41 to return again the shuttle to its neutral position, as shown in FIGURE 1.

In the larger sense the valves X and Y are serially related and form a composite auxiliary valving means which is externally actuated by release rod 23, for example, for providing selective communication between the inlet or source fluid and the operative shuttle extremity, so as to selectively force the valve shuttle to the left as indicated in FIGURE 3. By this means the source port may be isolated from the function port as above indicated and the pressure at the function port exhausted through the exhaust port 97.

In actual practice it is desired spring 78 be a go, no-go type spring which will permit valve opening at 40 pounds and above pressure but will insure valve closing for pressures 30 pounds or less; the safety factor of the 10 pounds pressure may be reduced where desired and if spring design so permits.

Valve 60 as seen in FIGURES 2, 5, and 6 permits the selected exhaust of the retainer line through port 52 and subsequently through exhaust port 97. Of course, such exhaust will not take place until the valve shuttle is shifted to the left as shown in FIGURE 3 and, further, until the pressure of the retainer line (at 55) is greater than the pressure at 52. Under normal conditions, however, the pressure of the retainer line will be equal to or less than that of the brake cylinder; hence the valve 60 will not function under ordinary situations until the valve shuttle 44 in FIGURE 3 has been actuated to the left and the braking pressure has been reduced sufliciently so that the retainer line pressure is greater than the same.

It will be seen that by virtue of the inclusion of spring 14, release rod 23 is in fact spring-loaded. Further spring means may be used, if desirable, for the release rod.

FIGURE 7 illustrates the operation of the system under normal conditions. It will be seen in FIGURE 7 that valve shuttle 44 is in its neutral position, isolating exhaust port 97 by virtue of the position of O-ring 52" and likewise assuring direct communication between ports 52 and 53, this by virtue of the provision of O-rings 52" and 53". Hence, communication is provided through line 109 of pressured media directly through the quick-release valve in its neutral position to the brake cylinder BC as indicated. Conventionally, of course, there will be provided a compressor C directly coupled to reservoir R, and an A-B valve A-B directly connected to the reservoir R as indicated. An engineers control ABC is provided for positioning the shuttle S of the A-B valve in an appropriate position. Retainer line R tee into line 109 by tee T and, correspondingly, tee T tees into retainer line R and leads via retainer line L to retainer line port 55. Retainer RT itself is directly connected to the tee T by line R, and a suitable control RC is provided the retainer to set the retained pressure at 0, 10, 20, or 30 pounds, or gradual release, for example. The retainer is conventional and is frequently used on down-hill runs to retain some, preset under pressure so that the train might not go down the grade too rapidly.

In addition, there is shown in FIGURE 7 a shuttle passageway P which is in selective alignment with line L and tee T so as to otter direct communication of pressured media through ports 53 and 52 to the braking cylinder BC, thus applying the brakes. A shift of the A-B valve by control ABC causes a registration (through passageway P") communication of lines R and R, and shifts passageway P out of communication between lines L and 100; correspondingly, there will be a release of pressure from the braking cylinder BC through ports 52, 53, the tee T and through the A-B valve, and is exhausted through retainer RT via lines R and R.

FIGURE 8 indicates the situation wherein the release rod 23 in FIGURE 1 has been actuated so as to depress instantaneously the valve stem 26 upwardly to open this valve. In such a situation the shuttle will be translated as indicated in FIGURES 3 and 8 so that reservoir pressure at 53 will be blocked and held by O-ring 53", brake pressure at function port 52 will be exhausted through 97, this by virtue of the O-rings 52 and 53', and, simultaneously, the pressure from the relief line L and hence will likewise be exhausted to passageway 67, valve .60, passageway 68, through port 52 and out exhaust port 97. Again, this retainer line pressure again will be exhausted only after the released brake pressure falls below the retainer line pressure. Hence, the retainer line pressure may be completely exhausted as indicated.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. A valve including, in combination, structure defining a valve chamber including an inner wall and, disposed therethrough, a medial function port, a source port disposed on one side thereof, and an exhaust port disposed on the remaining side thereof, all of said ports be ing mutually longitudinally spaced with respect to each other; a valve shuttle longitudinally slideably disposed within said chamber and having a medial portion spaced from said inner wall and a pair of mutually spaced, transverse valve lands disposed on respective opposite sides of said medial portion and slideable and sealingly engaging said inner wall, said valve lands being mutually spaced apart, and said chamber being so dimensioned that in valve neutral position said function and source ports are disposed between said valve shuttle lands and in valve operating position one of said lands is sealingly disposed between said function and source ports, interrupting communication therebetween, and the remaining valve land is disposed beyond said exhaust port, providing communication between said exhaust port and said function port, said remaining valve land during valve neutral position being sealingly disposed between said function and exhaust ports, said structure also being provided with an auxiliary outlet port disposed between said valve lands during valve neutral position and situated beyond said valve lands of said valve shuttle at valve operating position, said structure also being provided with an auxiliary inlet port disposed beyond said valve shuttle with respect to its valve lands during valve neutral position and also during valve operative position; auxiliary valve means for selectively providing communication between said auxiliary inlet port and said auxiliary outlet port for urging said valve shuttle into valve operating position; control means for selectively operating said auxiliary valve means; return means for returning said valve shuttle from valve operating position to val-ve neutral position when fluid pressure at said source port is reduced; and stop means for determining valve shuttle neutral position when said valve shuttle is returned thereto by said return means.

2. Structure according to claim 1 wherein said auxiliary valve means includes a spring biased, normally closed, selectively openable valve having a translatable valve stem, said structure including an enlarged bore receiving said valve stem, an inwardly urgeable plug fixed to said valve stem and slideably disposed within said enlarged bore, rockable actuating means disposed within said bore for urging said plug inwardly to open said valve, a multi-direction actuated, actuating arm integral with said rockable means and constructed for coupling to an external, m'anual actuatable means, and retainer means secured to said structure and over said rockable actuating means for retaining the latter within said bore.

3. Structure according to claim 1 wherein said auxiliary valve means comprises first and second, spring biased, normally closed, selectively openable valves serially interconnected and coupled between said outlet auxiliary outlet port and said auxiliary inlet port, means constructed for external actuation for selectively openmg said first valve, said second valve being so constructed and arranged with respect to said first valve that the former opens only when said first valve is selectively opened and pressured fluid passing through said first valve toward said second valve pressurizes said second valve with at least a certain minimum, pre-determined pressure, said second valve being so constructed and arranged that it will not open when said pressured fluid arriving thereat is below said minimum, pre-determined pressure.

4. Structure according to claim 1 wherein said auxiliary valve means comprises first and second, spring biased, normally closed, selectively openable valves serially interconnected and coupled between said outlet auxiliary outlet port and said auxiliary inlet port means constructed for external actuation for selectively opening said first valve, said second valve being so constructed and arranged with respect to said first valve that the former opens only when said first valve is selectively opened and pressured fluid passing through said first valve toward said second valve pressurizes said second valve with at least a certain minimum, ure-determined pressure, said second valve being so constructed and arranged that it will not open when said pressured fluid arriving thereat is within a range below said minimum, pre-determined pressure.

5. Structure according to claim 1 wherein said valve shuttle comprises a valve spool, said valve lands comprising transverse, peripheral, ring-like protuberances, said valve spool including an extension portion including a hollow bore originating at a reaction face within said valve spool and extending axially throughout said extension portion, said extension portion being disposed within said chamber and always communicating with said auxiliary inlet port, said extension portion being provided with perforations permitting communication of pressured fluid media from said auxiliary inlet port and through said perforations to said reaction face.

6. Structure according to claim 1 wherein said stop means comprises a threaded plug threada'bly secured to said structure to and within said chamber.

7. Structure according to claim ll wherein said structure includes a retainer line connection, passageway means disposed between said retainer line connection and said function port, and spring biased additional valve means disposed in said passageway between said function port and said retainer line connection.

8. Structure according to claim 5 wherein said ringlike protuberances include peripheral grooves, said valve spool including plural O-rings individually seated in respective ones of said peripheral grooves.

9. A valve including, in combination, structure defining a valve chamber including an inner wall and, disposed therethrough, a medial, function port, a source port disposed on one side thereof, and an exhaust port disposed on the remaining side thereof, all of said ports being mutually longitudinally spaced with respect to each other; a valve shuttle longitudinally slideably disposed within said chamber and having a medial portion spaced from said inner wall and a pair of mutually spaced, transverse valve lands disposed on respective opposite sides of said medial portion and slideably and sealingly engaging said inner wall, said valve lands being mutually spaced apart, and said chamber being so dimensioned that in valve neutral position said function and source ports are disposed between said valve shuttle lands and in valve operating position one of said lands is sealingly disposed between said function and source ports, interrupting communication therebetween, and the remaining valve land is disposed beyond said exhaust port, providing communication between said exhaust port and said function port, said remaining valve land during valve neutral position being sealingly disposed between said function and exhaust ports, said structure also being provided with an auxiliary outlet port disposed between said valve lands during valve neutral position and situated beyond said valve lands of said valve shuttle at valve operating position, said structure also being provided with an auxiliary inlet port disposed beyond said valve shuttle with respect to its valve lands during valve neutral position and also during valve operative position; auxiliary valve means for selectively providing communication between said auxiliary inlet port and said auxiliary outlet port for urging said valve shuttle into valve operating position; control means for selectively operating said auxiliary valve means; return spring means for returning said valve shuttle from valve Operating position to valve neutral position when fluid pressure at said source port is reduced; and stop means for determining valve shuttle neutral position when said valve shuttle is returned thereto by said return means.

10. Ina braking system for a railway car including a pressurized fluid reservoir, a braking cylinder for braking said car, and a control valve means coupled to and between said fluid reservoir and said braking cylinder for directing pressured fluid from said reservoir to said bralo ing cylinder during braking intervals and, subsequently, for directing pressured fluid from said braking cylinder for subsequent exhaust, an improvement comprising quick release valve means to exhaust the same to the external atmosphere while simultaneously blocking pressured fluid from said reservoir both from said braking cylinder and from exhaust, means for externally, selectively controlling said quick release valve neans, and means for automatically restoring said quick-release valve means to neutral condition once pressure of said pressured fluid blocked at said quick-release valve means is released, said quickrelease valve means being so constructed and arrange that, when in neutral position, it renders said braking system unaffected thereby in systerns normal operation, and wherein said improvement includes auxiliary valve means for rendering said quick release valve non-respon' sive to actuation of said selectively controlling means where operating pressure of said reservoir is below a predetermined minimum.

ll. In a braking system for railway cars including a pressured fluid reservoir, a braking cylinder for braking said car, an exhaust retainer for retaining desired fluid pressure during retainer exhaust, and a control valve means coupled to and etween said fluid reservoir and said braking cylinder, and also to and between said braking cylinder and said retainer, for directing pressured fluid from said reservoir to said braking cylinder during braking intervals and, subsequently, for directing pressured fluid from said braking cylinder to said retainer for subsequent exhaust, and improvement comprising quick-release valve means interposed between said control valve means and said braking cylinder for permitting the conducting of pressured fluid from said braking cylinder through said quick-release valve means to exhaust the same through said control valve and said retainer while simultaneously blocking pressured fluid from said reservoir both from said braking cylinder and from exhaust, said quick-release valve means having a neutral condition and being so constructed and arranged that when in neutral position, it renders said braking system unaffected thereby in the systems normal operation, means for externally, selectively controlling said quick-release valve means, and means for automatically restoring said quick-release valve means to neutral condition once pressure of said pressured fiuid blocked at said valve means is released, and wherein said improvement includes means coupled between said retainer and said quick release valve means for exhausting pressure at said retainer simultaneously with the exhausting pressure at said retainer simultaneously with the exhaust of pressure from said braking cylinder as aforementioned, and an auxiliary valve means for rendering said quick-release valve non-responsive to actuation of said selectively controlling means where operating pressure of said reservoir is below a predetermined minimum.

References Cited UNITED STATES PATENTS 7/1948 Klein 303 12/1954 Hobbs 251-325 XR 

1. A VALVE INCLUDING, IN COMBINATION, STRUCTURE DEFINING A VALVE CHAMBER, INCLUDING AN INNER WALL AND, DISPOSED THERETHROUGH, A MEDIAL FUNCTION PORT, A SOURCE PORT DISPOSED ON ONE SIDE THEREOF, AND AN EXHAUST PORT DISPOSED ON THE REMAINING SIDE THEREOF, ALL OF SAID PORTS BEING MUTUALLY LONGITUDINALLY SPACED WITH RESPECT TO EACH OTHER; A VALVE SHUTTLE LONGITUDINALLY SLIDEABLY DISPOSED WITHIN SAID CHAMBER AND HAVING A MEDIAL PORTION SPACED FROM SAID INNER WALL AND A PAIR OF MUTUALLY SPACED, TRANSVERSE VALVE LANDS DISPOSED ON RESPECTIVE OPPOSITE SIDES OF SAID MEDIAL PORTION AND SLIDEABLE AND SEALINGLY ENGAGING SAID INNER WALL, SAID VALVE LANDS BEING MUTUALLY SPACED APART, AND SAID CHAMBER BEING SO DIMENSIONED THAT IN VALVE NEUTRAL POSITION SAID FUNCTION AND SOURCE PORTS ARE DISPOSED BETWEEN SAID VALVE SHUTTLE LANDS AND IN VALVE OPERATING POSITION ONE OF SAID LANDS IS SEALINGLY DISPOSED BETWEEN SAID FUNCTION AND SOURCE PORTS, INTERRUPTING COMMUNICATION THEREBETWEEN, AND THE REMAINING VALVE LAND IS DISPOSED BEYOND SAID EXHAUST PORT, PROVIDING COMMUNICATION BETWEEN SAID EXHAUST PORT AND SAID FUNCTION PORT, SAID REMAINING VALVE LAND DURING VALVE NEUTRAL POSITION BEING SEALINGLY DISPOSED BETWEEN SAID FUNCTION AND EXHAUST PORTS, SAID STRUCTURE ALSO BEING PROVIDED WITH AN AUXILIARY OUTLET PORT DISPOSED BETWEEN SAID VALVE LANDS DURING VALVE NEUTRAL POSITION AND SITUATED BEYOND SAID VALVE LANDS OF SAID VALVE SHUTTLE AT VALVE OPERATING POSITION, SAID STRUCTURE ALSO BEING PROVIDED WITH AN AUXILIARY INLET PORT DISPOSED BEYOND SAID VALVE SHUTTLE WITH RESPECT TO ITS VALVE LANDS DURING VALVE NEUTRAL POSITION AND ALSO DURING VALVE OPERATIVE POSITION; AUXILIARY VALVE MEANS FOR SELECTIVELY PROVIDING COMMUNICATION BETWEEN SAID AUXILIARY INLET PORT AND SAID AUXILIARY OUTLET PORT FOR URGING SAID VALVE SHUTTLE INTO VALVE OPERATING POSITION; CONTROL MEANS FOR SELECTIVELY OPERATING SAID AUXILIARY VALVE MEANS; RETURN MEANS FOR RETURNING SAID VALVE SHUTTLE FROM VALVE OPERATING POSITION TO VALVE NEUTRAL POSITION WHEN FLUID PRESSURE AT SAID SOURCE PORT IS REDUCED; AND STOP MEANS FOR DETERMINING VALVE SHUTTLE NEUTRAL POSITION WHEN SAID VALVE SHUTTLE IS RETURNED THERETO BY SAID RETURN MEANS. 